Low power projection display devices

ABSTRACT

Described herein are devices that provide projection-type video output in a portable design. The projection-type display devices include a battery that stores electrical energy. The battery increases display device portability and flexible usage by permitting display device operation in locations not serviceable by a fixed power supply. For example, inclusion of a battery extends projector-type display device usage into a car, library, remote environment, or any other setting where fixed power outlets are not readily available or within power cord reach. To increase device endurance from a finite battery power supply, the present invention may also implement one or more hardware designs that reduce power consumption.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under U.S.C. §120 from co-pending U.S.patent application Ser. No. 10/891,840, filed Jul. 15, 2004 andentitled, “POSITIONABLE PROJECTION DISPLAY DEVICES”, which isincorporated herein for all purposes; the Ser. No. 10/891,840 patentapplication also claimed priority under 35 U.S.C. §119(e) fromco-pending U.S. Provisional Patent Application No. 60/487,868 filed Jul.16, 2003, which is incorporated by reference herein for all purposes;this application also claims priority under 35 U.S.C. §119(e) fromco-pending U.S. Provisional Patent Application No. 60/487,871 filed Jul.16, 2003, which is incorporated by reference herein for all purposes;this application also claims priority under 35 U.S.C. §119(e) fromco-pending U.S. Provisional Patent Application No. 60/487,691 filed Jul.16, 2003, which is incorporated by reference herein for all purposes;this application also claims priority under 35 U.S.C. §119(e) fromco-pending U.S. Provisional Patent Application No. 60/487,849 filed Jul.16, 2003, which is incorporated by reference herein for all purposes;this application also claims priority under 35 U.S.C. §119(e) fromco-pending U.S. Provisional Patent Application No. 60/487,744 filed Jul.16, 2003, which is incorporated by reference herein for all purposes.

BACKGROUND OF THE INVENTION

This invention relates to display devices that project an image. Moreparticularly, the present invention relates to projection-type displaydevices that may operate on battery power and increase usageflexibility.

Most computer systems employ a display device to output videoinformation to one or more users. Desktop computers, laptop computers,personal digital assistants (PDAs), video game consoles, cellulartelephones and digital video cameras output video information to anumber of video display technologies.

Cathode ray tube (CRT) monitors evolved from CRT televisions. Suchmonitors are heavy and large for their screen size relative to otherdisplay technologies. The footprint of a CRT monitor monopolizes usablespace on a table or desk. The weight and size of CRT monitors preventsportable use.

Liquid crystal display (LCD) displays are currently the leading displaytechnology for portable applications, but limit display area size to thedimensions of a device they are included with.

Projection-type display systems offer image sizes having diagonal spansup to 30 feet. Projected images allow numerous people to simultaneouslyview a projected image.

A recent increase in projector sales has been motivated by boardroom andclassroom usage where numerous people in a large space cansimultaneously view a projected image. Consumer demand in this aspect ofthe market has led manufacturers to evolve projectors towardsincreasingly powerful and feature-rich products.

Portability for the current designs is already hampered by size andweight. Moreover, due to the high power consumption of the currentdesigns, consumers are forced to rely on AC connectivity to a walloutlet or other fixed power supply. This connectivity requirementhandicaps portable usage.

Based on the foregoing, it should be apparent that portable visualoutput options are still limited; and that alternative portable visualoutput options would be desirable.

SUMMARY OF THE INVENTION

The present invention relates to devices that provide projection-typevideo output in a portable design. The projection-type display deviceincludes a battery that stores electrical energy. The battery increasesdisplay device portability and flexible usage by permitting displaydevice operation in locations not serviceable by a fixed power supply.To increase device endurance from a finite battery power supply, thepresent invention may also implement one or more hardware designs thatreduce power consumption.

In one aspect, the present invention relates to a projection-typedisplay device. The display device comprises a light source forgenerating light. The display device also comprises an opticalmodulation device for selectively transmitting light generated by thelight source according to video data included in a video signal providedto the optical modulation device. The display device further comprises aprojection lens system for outputting light transmitted by the opticalmodulation device along a projection path. The display deviceadditionally comprises at least one battery that stores electricalenergy. The display device also comprises an electrical energy transportsystem configured to transmit electrical energy from the battery to thelight source and to transmit electrical energy from the battery to theoptical modulation device.

In another aspect, the present invention relates to a display device.The display device comprises a base, a projection chamber, a positionalinterface and an electrical energy transport system. The base includesa) a housing, b) a light source within the housing for generating light,and c) a battery within the housing that stores electrical energy. Theprojection chamber comprises a) a projection chamber housing, b) anoptical modulation device for selectively transmitting light generatedby the light source according to video data included in a video signalprovided to the optical modulation device, and c) a projection lenssystem for outputting light transmitted by the optical modulation devicealong a projection path. The positional interface is coupled to the baseand coupled to the projection chamber; and allows the projection chamberto be moved relative to the base and allows the projection chamber tomaintain a constant position relative to the base after being moved. Theelectrical energy transport system is configured to transmit electricalenergy from the battery to the light source and to transmit electricalenergy from the battery to the optical modulation device.

These and other features of the present invention will be presented inmore detail in the following detailed description of the invention andthe associated figures.

Before committing to the Detailed Description, it may facilitateunderstanding to clarify certain words and phrases used in this patentdocument: the terms “include” and “comprise,” as well as derivativesthereof, mean inclusion without limitation; the term “or,” is inclusive,meaning and/or; the phrases “associated with” and “associatedtherewith,” as well as derivatives thereof, may mean to include, beincluded within, interconnect with, contain, be contained within,connect to or with, couple to or with, be communicable with, cooperatewith, be proximate to, be bound to or with, have, have a property of, orthe like. Support and definitions for certain words and phrases areprovided throughout this patent document, and those of ordinary skill inthe art should understand that in many, if not most instances, suchsupport applies to prior, as well as future uses of such words andphrases.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a top perspective view of a display device inaccordance with one embodiment of the present invention.

FIG. 2A shows a simplified top view schematic of components within abase of the display device illustrated in FIG. 1 in accordance with oneembodiment of the present invention.

FIGS. 2B and 2C illustrate simplified front and top perspective views,respectively, of a diode laser light source configuration in accordancewith another embodiment of the present invention.

FIG. 3A shows a simplified side view illustration of components withinthe projection chamber of FIG. 1 in accordance with one embodiment ofthe present invention.

FIG. 3B shows a front view illustration of the display device of FIG. 1with the positional interface and lower projection chamber cutaway toshow components therein in accordance with one embodiment of the presentinvention.

FIG. 4A illustrates a positional interface comprising a bendable tubingin accordance with one embodiment of the present invention.

FIG. 4B illustrates a cutaway front view of a display device and a balland socket positional interface in accordance with another embodiment ofthe present invention.

FIGS. 4C-F illustrate front, side and top views, respectively, of adisplay device and a dual hinge joint positional interface in accordancewith another embodiment of the present invention.

FIG. 5A illustrates a process flow for projecting video output from adisplay device in accordance with one embodiment of the invention.

FIG. 5B illustrates a process flow for projecting video output from adisplay device in accordance with another embodiment of the invention.

FIG. 6A illustrates a cutaway side view of a positional interfacecomprising a bendable tubing in accordance with one embodiment of thepresent invention.

FIG. 6B illustrates a top view of the display device of FIG. 6A with itsprojection chamber in a collapsed position when video output is notprojected.

FIG. 6C illustrates a front view of the display device base of FIG. 6Awith the bendable tubing removed to show the portions of the base forthe receiving tubing.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described in detail with reference toa few preferred embodiments thereof as illustrated in the accompanyingdrawings. In the following description, numerous specific details areset forth in order to provide a thorough understanding of the presentinvention. It will be apparent, however, to one skilled in the art, thatthe present invention may be practiced without some or all of thesespecific details. In other instances, well known process steps and/orstructures have not been described in detail in order to notunnecessarily obscure the present invention.

Projection type display devices of the present invention include abattery that stores electrical energy for powering electrical componentswithin the display device. The battery permits display device usage inareas and applications removed from a fixed power supply. For example,inclusion of a battery extends projector-type display device usage intoa car, library, coffee shop, remote environment, or any other settingwhere AC and fixed power outlets are not readily available or withinpower cord reach. Alternately, research and military personnel operatingin the field may benefit from portable display opportunities awarded bythe present invention. And unlike conventional power cord limiteddesigns, battery-based designs described herein permit operation ofdisplay devices in rooms and large spaces in locations far removed froma fixed power supply.

To increase display device endurance when relying on limited batterypower reserves, the present invention may reduce power consumptionwithin a projection type display device using one or more hardware orsoftware options. In one embodiment, an array of diode lasers ornon-lasing diodes generates light for subsequent optical modulationaccording to image data. Compared to conventional halogen and otherwhite light generating lamps, diode lasers offer a light generationoption that consumes significantly less power. Secondly, powerconsumption by fans employed for heat management within the displaydevice is decreased since the diode array generates significantly lessheat than a lamp. The diode array also outputs colored light, therebyeliminating the need for a color wheel and a motor that rotates thecolor wheel. This eliminates the power required for the color wheelmotor. In addition, this reduces the power required for managing heatproduced by the color wheel motor. In another embodiment, the displaydevice does not include audio output, which decreases size and reducespower consumption for the device.

FIG. 1 illustrates a top perspective view of a display device 10 inaccordance with one embodiment of the present invention. Display device10 produces and projects a video image for display on a receivingsurface; and comprises base 12, projection chamber 14, and positionalinterface 16.

Base 12 is configured to maintain the position of display device 10,e.g., relative to a stationary object. In one embodiment, base 12includes a relatively flat bottom that allows display device 10 to restupon a flat surface such as a table or desk. One or more high frictionpads 18 attach to a bottom surface 22 b of base 12 to increase staticfriction with the flat surface. Base 12 may also comprise a receivingslot 27 that allows modular attachment of functional accessories fordisplay device 10. For example, slot 27 may receive a clip attachmentthat comprises a spring-powered clip for clamping base 12 onto astationary object. This allows base 12 and display device 10 to bemounted on non-flat or non-horizontal surfaces such as vertical walls ofbookshelves and cubicles, and personal clothing or accessories such asbelts or straps, for example. Base 12 may also comprise another slot onits bottom side, dimensioned the same, to permit reception of thefunctional accessories on the bottom side of base 12.

A housing 20 protects internal components within base 12, defines outerdimensions of base 12, and defines dimensions of an inner light sourcechamber (FIG. 2). As shown, housing 20 is about rectangular andcomprises four sidewalls 22 c-f (only facing sidewalls 22 c and 22 d areshown in FIG. 1), top wall 22 a, and bottom wall 22 b. Walls 22 comprisea suitably stiff material that grants structural rigidity for base 12and mechanical protection for internal components within housing 20. Alightweight and stiff plastic or aluminum is suitable in this regard.One or more walls 22 of housing 20 may also include air vents 24 thatallow air flow between the inner chamber and an environment external tohousing 20. In another embodiment, housing 20 includes a more rounded orcontoured shape than that shown in FIG. 1 and does not includeorthogonal walls or a rectangular shape.

In one embodiment, base 12 is designed or configured to maintain balanceof display device 10. In this case, base 12 may be designed to maintainbalance for any position of projection chamber 14 relative to base 12while base 12 rests on a flat surface. Thus, components within base 12may be arranged and situated such that they cumulatively provide acenter of mass 23 relatively close to a geometric center for a footprintof base 12 (FIG. 2A). As shown in FIG. 2A, light source 64 and powersupply 66, which are typically the heaviest components in base 12, aredisposed relatively central to the footprint in one dimension and onopposite sides of center of mass 23 in the other dimension. In aspecific embodiment, components within base 12 are arranged within base12 according to their weight in order to substantially balance momentsabout a center of mass 23. The exact position of each component willdepend of on the number and type of components and base 12 layout. Inaddition, housing 20 may be sized to provide a wide enough footprint tobalance moments produced by positions and orientations of projectionchamber 14 away from a center of mass 23 for base 12.

Projection chamber 14 includes components responsible for the productionof images based on received light and received video data, andcomponents responsible for the projection of those images. Projectionchamber 14 comprises a projection chamber housing 32, an opticalmodulation device, and an output projection lens system. The opticalmodulation device selectively transmits light generated by a lightsource in base 12 according to video data included in a video signalprovided to the optical modulation device, and will be described infurther detail with respect to FIG. 3A. The projection lens systemoutputs light transmitted by the optical modulation device along aprojection path 31, and will also be described in further detail withrespect to FIG. 3A.

In operation, a light source within base 12 generates light which isprovided to the optical modulation device within projection chamber 14as a luminous flux. In one embodiment, one or more optical fiberstransmit light from the light source within base 12 to the opticalmodulation device within projection chamber 14. The optical modulationdevice selectively transmits light according to video data in a signalthat corresponds to an image to be projected. The projection lens systemenlarges and projects an image formed by the optical modulation device.Typically, the image is cast with a splay angle such that the imageenlarges as the distance to a receiving surface increases.

Projection chamber 14 comprises a projection chamber housing 32 thatprotects internal components of projection chamber 14; and defines outerand inner dimensions of projection chamber 14. As shown, housing 32 isabout cylindrical, except for an added receiving interface 29 on itsbottom side. Housing 32 has a cylindrical axis that is about collinearwith output projection path 31. An output optical projection lens 37 ofthe projection lens system forms and seals a forward end 14a ofprojection chamber 14. In a specific embodiment, the average diameter ofcylindrical housing 32 is relatively within 10 percent of the diameterof output lens 37. In another embodiment, projection chamber housing 32tapers slightly such that forward end 14a is slightly larger than an aftend 14b, resulting in a slightly frustoconical shape where lens 37constitutes the larger end. The present invention contemplates thatshape and design of projection chamber 14 may vary. For example, forwardend 14 a of projection chamber 14 may be rounded to accommodate acircular output lens 37 while aft end 14 b is cornered to accommodate arectangular optical modulation device and associated support componentsthat are locally contained better by a rectangular housing. Housing 32defines an inner chamber as described in further detail with respect toFIG. 3A. Housing 32 comprises a suitably stiff material for structuralrigidity of base 12 and internal component protection. A lightweight andstiff plastic or aluminum is suitable for most designs.

A receiving interface 29 is disposed on the lower side of projectionchamber 14 and permits coupling between projection chamber 14 andpositional interface 16. Interface 29 also permits containment andprotection of display device 10 components that do not entirely fitwithin projection chamber 14, or components that require spatialarrangements outside of projection chamber 14. In one embodiment,interface 29 comprises the same material as housing 32 and extends theinterior projection chamber provided by housing 32.

Positional interface 16 allows projection chamber 14 to be movedrelative to base 12, and allows projection chamber 14 to maintain aconstant position relative to base 12 after being moved. Thus,positional interface 16 allows a user to point projection chamber 14 andmanipulate the position of an output image projected by display device10 with ease. In one embodiment, positional interface 16 comprises aball and socket combination that permits relative rotational movementbetween projection chamber 14 and base 12. This embodiment will bediscussed in further detail with respect to FIG. 4B. In anotherembodiment, positional interface 16 comprises corrugated metal tubingthat is sufficiently stiff to hold a position for projection chamber 14,while compliant enough for a user to bend the tubing to achieve adesired position and orientation for projection chamber 14. Thisembodiment will be discussed in further detail with respect to FIG. 4A.

Positional interface 16 couples to base 12 and couples to projectionchamber 14. For the embodiment shown in FIG. 1, positional interface 16comprises an upper end 16 a that attaches to housing 32 of projectionchamber 14 and a lower end 16 b that attaches or couples to housing 20of base 12. More specifically, a housing 32 portion of receivinginterface 29 allows attachment to upper end 16 a, while a centralportion of top wall 22 a allows attachment to lower end 16 b. As shown,positional interface 16 couples to housing 32 at a location between anaft end of projection chamber 14 and a forward end that includes outputlens 37.

In one embodiment, upper end 16 b of positional interface 16 couples ata location relatively close to a center of mass 25 of projection chamber14 to minimize mechanical moments transmitted onto base 12, e.g., thoseresulting from a displacement of center of mass 25 away from a center ofmass 23 for base 12. In another embodiment, base 12 includes a recessedgroove in top wall 22 a that allows positional interface 16 to be foldedor collapsed down into top wall 22 a, thereby decreasing the profile ofdisplay device 10 during non-use.

FIG. 2A shows a simplified top view schematic 50 of components withinbase 12 in accordance with one embodiment of the present invention. Alight source chamber 65 is defined in volume and shape by inside walls22 a-f of base 12. Light source chamber 65 comprises fans 62, lightsource 64, power supply 66, fiber-optic interface 70, fiber-optic 72,input output circuitry 74, control circuitry 76, and input/outputinterfaces 78.

Fans 62 a and 62 b move air through light source chamber 65 for coolingcomponents within light source chamber 65. In one embodiment, fans 62draw air in through inlet air vents 24 a on one side of base 12 andexhaust heated air out of exhaust air vents 24 b after the air hascooled internal components of base 12 and walls of housing 20. Oneskilled in the art will appreciate that fan 62 and vent 24 placementwill vary with internal component placement within light source chamber65. Specifically, fan 62 placement—and airflow patterns effected by fans62 within light source chamber 65—is designed according to individualtemperature regulation requirements and heat generation contributions ofcomponents within base 12. Typically, light source 64 and power supply66 generate the largest proportion of heat within base 12, while controlcircuitry 76 and input/output circuitry 74 call for tighter temperatureregulation. Correspondingly, inlet air 69 passes in through inlet airvents 24a, initially passes and cools control circuitry 76 andinput/output circuitry 74 while the air is relatively cool, passesacross power supply 66 and light source 64, and exits out exhaust airvents 24 b. The exhaust air may also cool fan motors 63 a and 63 b,which rotate fans 62 a and 62 b, respectively. In one embodiment,multiple fans 62 are used to permit a lower profile for base 12. As oneskilled in the art will appreciate, the number and size of fans 62 usedwill depend on heat generation within display device 10 and a desiredair flow to maintain one or more heat dissipation goals. Light sourcechamber 65 may also include one or more vertical or horizontal airflowguides 67 within light source chamber 65 to direct and distributeairflow as desired. In one embodiment, light source 64 comprises one ormore diode laser arrays and one or more circuit boards to power andcontrol the diode lasers. In this case, airflow guides 67 are arrangedto direct cooling air across the surfaces of each circuit board. As willbe described in further detail below, fans 62 a and 62 b may also beresponsible for drawing air through positional 16 interface and to orfrom projection chamber 14 to cool the optical modulation deviceincluded therein.

Light source 64 is arranged within housing 20 and generates light.Display device 10 may employ a number of light generating technologiesand configurations for generating light, each of which includes its ownset and arrangement of light generation and light manipulationcomponents. In one embodiment, display device 10 comprises diode lasersfor light generation and consumes less than about 50 watts whenoutputting a projected image.

FIGS. 2B and 2C illustrate simplified front and top perspective views,respectively, of a light source configuration in accordance with anotherembodiment of the present invention. In this case, light source chamber65 includes an array of lasers 96 that generate collimated light. Lasers96 may comprise diode lasers and diode pumped solid-state (DPSS) lasers,for example. The collimated light produced by a diode laser differs fromradiant light and is characterized by light that is output with aboutthe same output direction, and significantly in phase.

The array of lasers may comprise one or more red diode lasers 96 a orred DPSS lasers 96 a, one or more green DPSS lasers 96 b, and one ormore blue diode lasers 96 c or blue DPSS lasers 96 c. The number andpower of lasers for each color is scaled according to a desired lightintensity output for display device 10 and according to the lightsensitivity of a viewer to each color, as one skilled in the art willappreciate. Each laser 96 is installed on a circuit board 97, whichmounts, and provides electrical control for, each laser 96 installedthereon. Multiple lasers 96 may be mounted on a single board 97 toreduce space occupied by light source 64. Including multiple lasers 96for a single color allows output luminosity of display device 10 to varywith the number of lasers 96 turned on for each color, and allows forredundant control of light generation by diode lasers 96. Thus, one ormore of the lasers may be turned off if less light intensity is desired,longevity of individual lasers 96 benefits from periodic shut-down, orpower conservation for display device 10 is preferred. In oneembodiment, each diode laser in the array consumes less than about 10watts when generating light. Further description of laser-basedprojection systems suitable for use with the present invention aredescribed in commonly owned and co-pending patent application entitled“PROJECTION-TYPE DISPLAY DEVICES WITH REDUCED WEIGHT AND SIZE”, namingWilliam J. Plut as inventor, and filed on the same day as thisapplication. This application is incorporated by reference in itsentirety for all purposes.

In one embodiment, light output from the lasers is provided tofiber-optic cabling 72. Fiber-optic cabling 72 includes one or morefiber optic cables that transmit light from each laser 96 along multipleor common optical paths to relay optics system 106 and 108 disposedalong a light path between an exit end of fiber-optic cabling 72 and anoptical modulation device 44 (FIG. 3A). Each cable 72 has an inlet end72 a that receives light from a laser 96 and an outlet end 72 b thatoutlets the laser light for transmission to relay optics 106 and 108,and subsequent transmission to optical modulation device 44. Sincefiber-optic cabling 72 may be bent and flexibly positioned, cabling 72advantageously allows light transmission between lasers 96 and relayoptics system regardless of the positioning and orientation between thelasers and optics system. For example, this allows flexible arrangementof lasers 96, relay optics 106 and 108 and prism 110 (FIG. 3A), whichmay be used to improve space conservation within base 12, decrease thefootprint of base 12, and minimize display device 10 size. In addition,flexible fiber-optic cabling 72 also allows positional interface 16 tomove without compromising light provision to the optical modulationdevice in projection chamber 14.

The number of fiber optic cables in cabling 72 will vary with design.Multiple fiber-optic cables 72 may be employed in a design where eachcable 72 services one or more lasers. As shown in FIG. 2D, light fromeach laser 96 is first transmitted into a fiber-optic cable 72 dedicatedto each laser; and subsequently routed and transmitted into a commonfiber-optic cable 71. Each laser dedicated fiber-optic cable 72 thusreceives laser light from an individual laser 96, and transmits thelight to junction 75. In one embodiment, each fiber-optic cable 72attaches directly to an individual laser 96. For example, eachfiber-optic cable 72 may include a fixture with an inner threadedinterface that matches a threaded interface disposed on an outsidesurface of a diode laser 96 housing. Commercially available fiber-opticcables, such as that available from Ocean Optics Inc. of Dunedin, Fla.,may come standard with such coupling and alignment fixtures. In aspecific embodiment, a short focal length normal or GRIN lens is mountedat the inlet end of each cable 72 to facilitate laser-to-fiber lighttransition and collimated transfer into cable 72.

Junction 75 permits transmission of light from fiber-optic cables 72into converging optics 77, and into common fiber-optic cable 79.Converging optics 77 redirect incoming light from each fiber-optic cable72 into common fiber-optic cable 79 and comprise a converging lens 77 athat redirects light toward re-collimating lens 77 b, which collimatesand re-directs incoming laser light from converging lens 77 a intocommon optical fiber 79. Although not shown, junction 75 may alsoinclude a rigid structure, such as a suitably dimensioned moldedplastic, that fixtures (holds and positions) fiber-optic cables 72 and79. In a specific embodiment, junction 75 comprises an optical adhesivethat adheres cables 72 directly to lens 77 a. In another specificembodiment, the outlet end 72 b the fiber-optic cables 72 are combinedinto a larger cable 71 that contains multiple fibers. Multiple fibercables, such as fiber ribbon-based cables and those that employ multiplefibers located circumferentially within a round tube, are commerciallyavailable from a variety of vendors.

Multiple fiber-optic cable designs may be employed where each cabletransmits a primary color. For example, three fiber-optic cables may beemployed in which each cable transmits light from a primary color set oflasers along three different optical paths to three primary colordedicated optical modulation devices. Alternately, as shown in FIG. 2D,a common fiber-optic cable may be used to transmit sequentially emittedred, green and blue light along a common light path to a singlemirror-based optical modulation device 44. Fiber-optic cabling 72 maycomprise single mode or multimode fibers such as those readily availablefrom a wide variety of vendors known to those skilled in the art. Insome cases, a converging lens is disposed at outlet end 72 b whenfiber-optic cable 72 is a single mode fiber to correct for anydivergence resulting from light transmission within the single modefiber-optic cable 72.

One advantage of diode lasers for light generation is that the diodelasers each output relatively monochromatic colored light, therebyeliminating the need for a color wheel and its associated spatialrequirement; and eliminating the color wheel motor which also occupiesspace, consumes power and generates heat. In addition, the highlycollimated and smaller cross-sectional area laser output needs lessspace and smaller optics for cross-sectional area manipulation thanlight output by a lamp, saving significant space that would otherwise berequired for larger light condensing lenses and their required focallengths for condensing of light generated by a white light lamp.Further, frame and color sequential information output by a diode laserlight generation system can be digitally synchronized faster and withgreater precision than with a mechanical color wheel system. Outputlenses for each diode laser may also include custom shaping thatcorrects for any astigmatism and divergence provided by the diode lasergenerator. Further description of astigmatism and divergence correctinglenses are described in commonly owned and co-pending patent applicationentitled “PROJECTION-TYPE DISPLAY DEVICES WITH REDUCED WEIGHT AND SIZE”,which was incorporated by reference above.

Returning back to FIG. 2A, inner light chamber 65 may also employ otherlight source arrangements to generate light for display device 10. Somelight source arrangements, for example, may comprise an array of radiantlight emitting diodes (characterized by radiant, non-lasing ornon-collimated light generation). Similar to diode and DPSS lasers,radiant light emitting diodes consume less power and generate less heatthan a white light lamp, and also emit colored light and thereby mayoperate without a color wheel. Light chamber 65 may also include one ormore dichroic mirrors in white light generation assemblies to separatered, green and blue light for transmission within fiber optic cables 72to color dedicated optical modulation devices, such as three liquidcrystal display (LCD) valves employed for red, green and blue control.

Returning to FIG. 2A, at least one battery 66 is configured to provideelectrical power to light source 64 and other components within displaydevice 10 that rely on electrical power. Thus, battery 66 provideselectrical energy to control circuitry 76, input/output circuitry 74,fans 62, power diode 80, and components within projection chamber 14such as optical modulation device 102 (FIG. 3A). A power cord port 81receives a power cord, which couples power supply 87 to an AC powersource such as a wall power supply. In one embodiment, conversion of ACpower to DC power occurs in a transformer included between ends of thepower cord, as is common with many laptop computer power cords, therebyreducing the size of power supply 66, base 12 and display device 10 andincreasing portability of display device 10. Circuitry within powersupply 87 may then convert incoming power to one or more DC voltages forspecific components in display device 10.

At least one battery 66 is included in housing 32 to store electricalenergy. An electrical energy transport system 71 is in electricalcommunication with battery 66 and with various components within displaydevice 10; and transfers electrical energy from battery 66 to thevarious components. For example, electrical energy transport system 71includes electrical communication 71 a between battery 66 and lightsource 64 and electrical communication 71 b between battery 66 and theoptical modulation device 102 in projection chamber 14.

In one embodiment, battery 66 is rechargeable. In this case, a lithiumion battery is suitable for use as battery 66. Lithium ion batteries arewidely available from a variety of vendors that are well known in theart, such as those that supply the laptop computer market. Battery 66may be recharged using power provided through inlet port 81. Battery 66allows display device 10 to operate on stored energy and withoutreliance on proximity to an AC power source, which further increasesportability of display device 10.

In a specific embodiment, battery 66 stores between about 50 watt hoursand about 200 watt hours of electrical energy. For some designs, betweenabout 50 watt hours and about 100 watt hours of electrical energy may besuitable. The number of batteries in battery 66 will depend on powerconsumption for a display device, the energy stored in each battery, anda desired operational life on a given battery capacity for the displaydevice. In one embodiment, display device 10 comprises between one andfour 50 watt hour batteries within base 12.

An electrical energy transport system 71 is in electrical communicationwith battery 66 and with various components within display device 10;and transfers electrical energy from battery 66 to the variouscomponents. For example, electrical energy transport system 71 includeselectrical communication 71 a between battery 66 and light source 64 andelectrical communication 71 b between battery 66 and the opticalmodulation device 102 in projection chamber 14. Electrical energytransport system 71 includes one or more wires, electrical connectors,pinned and multiple line electrical cables, printed circuit boardcircuits, switches to control current flow, etc. Electricalcommunication 71 b, for example, comprises one or more electricalconnectors that travel through positional interface 16 from base 12 toprojection chamber 14, as will be described in further detail below withrespect to FIGS. 4A-4F. Electrical energy transport system 71 is thusconfigured to deliver electrical energy from the battery to the lightsource and to transmit electrical energy from the battery to the opticalmodulation device. Other components having electrical communication withbattery 66 through system 71 include control circuitry 76, input/outputcircuitry 74, fans 62, power diode 80.

Electrical energy transport system 71 cooperates with battery 66 topower light source 64 and other components within display device 10 thatconsume electrical power for operation. Thus, battery 66 provideselectrical energy to control circuitry 76, input/output circuitry 74,fans 62, power diode 80, and components within projection chamber 14such as optical modulation device 102 (FIG. 3A). In a specificembodiment, battery 66 stores between about 50 watt hours and about 200watt hours of electrical energy. For some designs, between about 50 watthours and about 100 watt hours of electrical energy may be suitable. Thenumber of batteries in battery 66 will depend on power consumption for adisplay device, the energy stored in each battery, and a desiredoperational life on a given battery capacity for the display device. Inone embodiment, display device 10 comprises between one and four 50 watthour batteries within base 12.

Inlet power port 81 receives a power cord, which electrically couplesdisplay device 10 to an AC power source such as a wall power supply. Inone embodiment, the power cord comprises a transformer that converts ACelectrical power to DC electrical power before receipt of the DC powerby the display device at the inlet power port 81. Thus, conversion of ACpower to DC power occurs in a transformer included between ends of thepower cord, as is common with many laptop computer power cords; therebyreducing the size of power supply 66, base 12 and display device 10 andincreasing portability of display device 10. Power circuitry 87 convertsincoming power from the power cord to one or more DC voltages usedwithin display device 10 to allow display device 10 to run from a fixedpower supply when battery 66 is not used. In addition, power circuitry87 is also recharges battery 66 when the power cord provides power toport 81.

At least one fiber-optic cable 72 transmits light from light source 64to relay optics (FIG. 3A) disposed along a light path between an exitend of fiber-optic cable 72 and an optical modulation device (FIG. 3A)in projection chamber 14. With respect to device 10 structure,fiber-optic cable 72 transmits light from one compartment to a separatecompartment, namely, from light source chamber in base 12 to projectionchamber 14. The number of fiber optic cables will vary with design. Asmentioned above, multiple fiber-optic cables may be employed in a laserlight generation design, for example, where each cable 72 services oneor more diode lasers. Alternatively, each cable 72 may service a primarycolor. One or more fiber-optic cables 72 may also be used to transmitlight from a lamp. For example, one fiber-optic cable may be used totransmit sequentially controlled red, green and blue generated by adiode laser array and transmitted along a single light path to a singlemirror-based optical modulation device. Three fiber-optic cables may beemployed to transmit light from a) a single lamp that outputs whitelight which is subsequently separated into three primary colors, or b) alaser array that outputs red, green and blue light into threefiber-optic cables, to three optical modulation devices that are eachdedicated to modulation of a primary color.

Fiber optic interface 70 facilitates transmission of light from eachlaser into fiber-optic cabling 72 (FIG. 2A). Interface 70 may includeone or more fixtures that position and hold an inlet end for eachfiber-optic cable included in cabling 72 such that light output from thelight source transmits into a fiber-optic cable. Interface 70 may alsoinclude optics that direct light from lasers into cabling 72. In oneembodiment, a single fiber-optic cable is used in cabling 72 and fiberoptic interface 70 includes a lens system disposed between the outlet ofa lamp or each laser and the inlet of the single fiber-optic cable todirect light into the cable. The lens system may comprise at least twolenses: a first lens to direct the light towards the fiber entrance anda second lens that collimates light entering the cable. In anotherembodiment that implements a one-to-one laser to fiber-optic cable 72relationship, fiber optic interface 70 holds the inlet end for eachfiber-optic cable 72 relatively close to the outlet of each laser toreceive light therefrom. Each cable in this case may include aconverging lens at its inlet end that facilitates light capture andtransmission into a cable. In another one-to-one design, eachfiber-optic cable in cabling 72 includes a fixture that permitsattachment to another object. For example, conventionally availablefiber-optic cables available from vendors such as Ocean Optics Inc. ofDunedin, Fla. include a detachable fixture with a thread that allowsscrewing and fixing of the fiber-optic cable to a mating thread disposedon a laser housing. In this case, fiber-optic interface 70 comprises thethreaded fixture from each cable and the mating thread on the laser.

In a single path embodiment where red, green and blue lasers transmitscolored light to a single optical modulation device along a singlefiber-optic cable 72, fiber-optic interface 70 receives colored lightfrom each colored laser, in turn, according to timed control signalsprovided to the lasers by control circuitry 76. In a single pathembodiment where a white light generating lamp transmits sequentialcolored light to a single optical modulation device within projectionchamber 14 along a single fiber-optic cable 72, fiber-optic interface 70receives colored light from integrator tunnel 95 and transmits thecolors passively—and a color wheel controls sequential provision ofcolored light. Generally speaking, construction of fiber-optic interface70 varies with the generation nature and arrangement of light source 64,as well as the light manipulation device immediately upstream in thelight path from interface 70. For a lamp light source 64 configurationthat transmits light through an integrator tunnel 95 and condensing lens94 before light receipt by interface 70, interface 70 may be disposed ata focus of the condensing lens 94 to minimize interface 70 size. In thiscase, interface 70 may also include one or more lenses that straightenconverging light for travel down fiber-optic cable 72.

Input/output circuitry 74 provides an interface between controlcircuitry 76 and one or more interfaces, or ports, 78 (FIG. 2A). Inputports 78 are configured to receive at least one cable, wire, orconnector, such as a cable for transmitting a video signal comprisingvideo data from a digital computing device. Common ports suitable foruse with input ports 78 include ports that receive S video cable, 6-pinmini DIN, VGA 15-pin HDDSUB female, an audio cable, component RCAthrough an S-Video adaptor, composite video RCA cabling, a universalserial bus (USB) cable, fire wire, etc. Ports 78 may also include anaudio output port for wired connection to speakers employed by aheadphone or speaker system.

Control circuitry 76 provides control signals to components within base12 and routes data from input/output circuitry 74 to appropriatecomponents within display device 10. Thus, control circuitry 76 providescontrol signals to light source 64 that determine when light source 64is turned on/off. In addition, circuitry 76 may include and accessmemory that stores instructions for the operation of components withindisplay device 10. For example, circuitry 74 may provide control signalsto control fans 24 according to stored heat regulation instructions. Oneor more sensors may also be disposed within base 12 to facilitatethermal regulation. For example, a temperature sensor may be disposedproximate to circuitry 74 and 76 to monitor temperature levels andparticipate in closed loop temperature control within base 12 ascontrolled by control circuitry 76.

Input/output circuitry 74 and input ports 78 collectively permitcommunication between display device 10 and a device that outputs avideo signal carrying video data. For example, desktop computers, laptopcomputers, personal digital assistants (PDAs), cellular telephones,video game consoles, digital cameras, digital video recorders, DVDplayers, and VCRs, may all be suitable to output video data to displaydevice 10. Video data provided to control circuitry 76 may be in ananalog or digital form. In some cases, input/output circuitry 74 andcontrol circuitry 76 convert analog video signals into digital videosignals suitable for digital control of an optical modulation deviceincluded in display device 10, such as a liquid crystal display “LCD”device or a digital micromirror “DMD” device. Thus, input/outputcircuitry 74 or control circuitry 76 may also include support softwareand logic for particular connector types, such as processing logicrequired for S-video cabling or a digital video signal. Controlcircuitry 76 may also include and access memory that facilitatesconversion of incoming data types and enhances video compatibility ofdisplay device 10. Suitable video formats having stored conversioninstructions within memory accessed by control circuitry 76 may includeNTSC, PAL, SECAM, EDTV, and HDTV (1080i and 720p RGBHV), for example.

When lasers 96 are used for light generation within light source 64(FIG. 2C), control circuitry 76 receives video data included in a signalvia one or more input ports 78 and input/output circuitry 74, convertsthe data to color frame sequential data, and synchronizes the framesequential data for delivery to the optical modulation device 102 (FIG.3A) and to each laser 96. In a single path design between lasers 96 andthe optical modulation device where one optical fiber transmits red,green and blue light in a time controlled sequential order, thisincludes synchronizing the timing of data sent to the optical modulationdevice and on-off commands sent to lasers 96.

Power diode 80 (FIG. 2A) is electrical communication with an externalpower switch 82 (FIG. 1) and illuminates when display device 10 isturned on to indicate whether display device 10 is on or off.

FIG. 3A shows a simplified side view illustration of components withinprojection chamber 14 of FIG. 1, taken through a vertical midpoint ofchamber 14 along its cylindrical axis, in accordance with one embodimentof the present invention. FIG. 3B shows a front view illustration ofdisplay device 10 with positional interface 16 and lower projectionchamber 29 cutaway to show components therein. Projection chamber 14comprises optical modulation device 102, fiber-optic interface 104,relay optics 106 and 108, prism structure 110, projection lens system112, control and power cabling 120, and air duct 122.

Fiber-optic cable 72 attaches to a fiber-optic interface 104 and outputslight to relay optics 106. In one embodiment, fiber-optic interface 104secures fiber-optic cable 72 such that slack is provided for fiber-opticcable between attachment at fiber-optic interface 104 and attachmentwithin base 12. The slack allows fiber-optic cable 72 to deflect withpositional interface 16 for various positions of projection chamber 14relative to base 12.

Together, fiber-optic cable 72 and fiber-optic interface 104 directlight generated by light source 64 to prism 110. In one embodiment,fiber-optic cable 72 and interface 104 are configured with respect toprism 110 so as to provide an optical path of incident light that isabout perpendicular to an incident surface of prism 110. Some digitalmicromirror light modulator designs require that incoming light beincident on the light modulator from either above or below its lightreflecting surface to allow light output along output path 31. Interface29 of projection chamber housing 32 and fiber-optic interface 104 easethis requirement and allow a designer to arrange fiber-optic cable 72and fiber-optic interface 104 within interface 29 such that fiber-opticinterface 104 directs light at a particular desired angle relative toprism 110, and onto optical modulation device 102. For example,fiber-optic interface 104 may be coupled to interface 29 to provide anincident light path that is perpendicular onto an incident surface ofprism 110 and has a 45 degree angle relative to optical modulationdevice 102 (e.g., prism 110 is rotated 45 degrees about path 31).Attachment between interface 104 and housing 29 maintains the desiredincoming light angle despite changing positions of fiber-optic cable 72along its length caused by repositioning of positional interface 16.

Relay optics 106 and 108 convert light receive from fiber-optic cable 72to light suitable for transmission into prism structure 110 and ontooptical modulation device 102. This may include shaping and resizinglight flux received from cable 72 using one or more lenses. When lightsource 64 comprises a lamp 91 and uses a downstream optical integrator95 as illustrated in FIG. 2B, lens 106 is selected and arranged withininterface 29 of projection chamber 14 to increase the area of light fluxreceived from fiber-optic cable 72. Lens 108 is then selected andarranged to convert the divergent light transmitted by lens 106 intosubstantially parallel flux for transmission into prism 110 and ontooptical modulation device 102.

In another embodiment, display device 10 comprises a pair of fly-eyelenses arranged in the optical path between light source 64 and prism110. Cumulatively, the pair of fly-eye lenses uniformly distribute lightreceived from fiber-optic cable 72 to the flux transmitted upon opticalmodulation device 102. In a specific embodiment, the pair of fly-eyelenses are arranged on either and a fiber-optic cable 72. The firstfly-eye lens is disposed at fiber-optic interface 70 within base 12,receives light from a lamp or diode laser array, and spatially dividesthe entire input light flux into a set of blocks or components that eachcomprise a portion of the total area of the inlet flux. Light for eachblock or component then travels down its own fiber-optic cable 72. Thesecond fly-eye lens comprises the same number of blocks or componentsand is disposed at relay lens 106. The second fly-eye lens receives afiber-optic cable for each block or component, and outputs light foreach component such that the light from each component is expanded tospan the downstream dimensions of optical modulation device 102 and theprojected image.

Prism structure 110 is an optical modulation system that provides lightto optical modulation device 102 at predetermined angles. Prismstructure 110 also transmits light from optical modulation device 102 tothe projection lens system 112 along output path 31. Prism structure 110comprises prism components 110 a and 110 b that are separated by airspace or bonding interface 110 c. Interface 110 c is disposed at such anangle so as to reflect light provided from fiber-optic cables 72 (andintermittent relay optics) towards optical modulation device 102. Inaddition, interface 110 c allows light reflected by optical modulationdevice 102 to transmit to projection lens system 112 along output path31.

Optical modulation device 102 is configured to selectively transmitlight to provide an output image along output light path 31. To do so,optical modulation device 102 is supplied with video data included in avideo signal and selectively transmits light according to the videodata. The video data is typically provided to device 102 on a frame byframe basis according to individual pixel values. If the video data isnot received by display device 10 in this format, control circuitry 76in base 12 may convert the video data to a suitable format for operationof optical modulation device 102. In one embodiment, individual lightmodulation elements within optical modulation device 102, which eachcorrespond to an individual pixel on the output image, translatereceived digitized pixel values into corresponding light output valuesfor each pixel.

In a specific embodiment, optical modulation device 102 is a mirrorbased optical modulation device, such as a digital micromirror device(or DMD, a trademark of Texas instruments Inc.) commercially availablefrom Texas Instruments, Inc. In this case, optical modulation device 102comprises a rectangular array of tiny aluminum micromechanical mirrors,each of which individually deflects about a hinged axis to selectivelyreflect output image light down output path 31, and reflect non-imagelight away from output path 31. The deflection state or angle of eachmirror is individually controlled by changing memory contents of anunderlying addressing circuit and mirror reset signal. The array ofmirrors is arranged such that each mirror is responsible for lightoutput of a single pixel in the video image. Control signalscorresponding to pixel output are supplied to control electrodesdisposed in the vicinity of each mirror, thereby selectively deflectingindividual mirrors by electromagnetic force according to video data on apixel by pixel basis. Light reflected by each mirror is then transmittedalong output light path 31, through prism structure 110, and out ofprojection chamber 14 using projection lens system 112.

A controller 114 is included with optical modulation device 102 andprovides control electrical signals that direct each micromechanicalmirror to desired light reflecting states corresponding to pixel videodata for each pixel. Control and power cabling 120 provides electricalcommunication between controller 114 and control circuitry 76 in base 12(FIG. 2A). Thus, at least one electrical connector included in cabling120 couples to controller 114 in projection chamber 14 and to controlcircuitry 76 in base 12 and provides electrical communicationtherebetween. A power line within cabling 120 extends between opticalmodulation device 102 in projection chamber 14 and power supply 66 inbase 12 and provides power from power supply 66 to device 102. Controland power cabling 120 then travels through positional interface 16,which includes one or more holes or apertures that allow connector 120to pass therethrough without impingement on cabling 120 for any positionof projection chamber 14. In one embodiment, cabling 120 passes througha plastic tube in positional interface 16 to further protect the wires.

The illumination angles for optical modulation device 102 are set by theoutput direction of fiber-optic interface 102, arrangement of relayoptics 106 and 108, and the faces of prism structure 110. After lightreflection by individual mirrors of optical modulation device 102,reflected light exits prism structure 110 towards lenses 112 alongoutput optical path 31.

Vents 118 are disposed on an aft portion of housing 32 proximate tooptical modulation device 102. An air duct 122 includes a high-pressureend proximate to optical modulation device 102 and controller 114, and alow pressure end disposed within base 12 (see also duct 210 of FIG. 4A).As mentioned above with respect to FIG. 2A, fans 62 draw air from withinbase 12 and exhaust the air out exhaust vents 24b, which creates anegative pressure within base 12 relative to the ambient room orsurroundings. Correspondingly, fans 62 create a negative pressure forthe end of duct 122 within base 12 relative to the opposite end inprojection chamber 14, which would otherwise rest at room pressure dueto vents 118. By disposing one end of air duct 122 within base 12 andthe other end in a space 125 around optical modulation device 102, fans62 thus draw air from a space 125 and cool optical modulation device102. Cumulatively, cooling air is drawn from the ambient surroundingsaround projection chamber 14, through vents 118 and into a space 125surrounding optical modulation device 102, into duct 122 at end 122 a,through duct 122, out duct 122 at end 122 b, into base 12, and out airvents 24 b. Continually running fans 62 maintains end 122 b at a lowpressure relative to end 122 a, and thus provides continual cooling foroptical modulation device 102.

Either end of duct 122 may include an opening or aperture thatfacilitates cooling of optical modulation device 102 and air flow withindisplay device 10. For example, end 122 a may include a rectangular andelongated opening 223 that spans the width of optical modulation device102 (FIG. 4A). In addition, end 122 b may include a large funnel openingthat increases the air outlet area 122 b within base 12. This largeopening increases airflow in duct 122 and increases air removal fromspace 125 in projection chamber 14. In one embodiment, end 122 b has alarger opening than end 122 a. When a rectangular opening for end 122 ais disposed relatively close to controller 114 and optical modulationdevice 102, and on a bottom side of projection chamber 14 relative totop vents 118, downward vertical flow across the entire width of opticalmodulation device 102 and controller 114 may result. Further, as will bediscussed with respect to FIG. 4A, duct 122 may also include a valvecontrolled by control circuitry 76 that closes duct 122 when fans 62 arenot in use to prevent hot air from base 12 from flowing to projectionchamber 14.

In another embodiment, heat dissipation for optical modulation device102 includes one or more heat sinks in heat conduction communicationwith metal components of optical modulation device 102. For example, aheat channel comprising metal or another high conduction material maycontact metal components of optical modulation device 102 and transmitheat generated by optical modulation device 102 to another metallicstructure within display device 10, such as projection chamber housing32 (when comprised of metal) or a corrugated metal tubing included inpositional interface 16 (FIG. 4A).

Output projection path 31 (FIG. 3A) characterizes: a) the direction ofimage light selectively transmitted by optical modulation device 102within projection chamber 14, and b) the direction of light output fromprojection chamber 14. Within chamber 14, path 31 extends as a straightline from optical modulation device 102 for elements in their ‘on’state, through prism structure 110, and out projection lens 37.

A projection lens system 112 is disposed along output path 31 foroutputting light transmitted by the optical modulation device along path31. Projection lens system 112 manipulates image light transmitted byoptical modulation device 102 along output path 31 such that a projectedimage cast on a receiving surface enlarges as distance from output lens37 to the receiving surface increases. Projection lens system 112comprises lenses 112 a, 112 b, 112 c and external lens 37, each of whichare disposed centrically along and orthogonal to output light path 31.Distances between each lens 112 may vary with a desired splay angle fromoutput lens, as may the number of lenses 112 used. In one embodiment,display device 10 is designed for a short throw distance, such asbetween about six inches and about 15 feet. Display device 10 may alsoinclude one or more buttons or tools that allow a user to manually focusand manually zoom output from projection lens system 112. Projectionchamber 14 may also include a lens between optical modulation device 102and prism 110 that converges image light reflected by device 102 towardsoutput optical path 31. This allows a reduction in output lens 112diameters, and a corresponding reduction in diameter and size forprojection chamber 14.

Although the present invention has been described primarily so far withrespect to a display device that employs a reflective light modulator ofa digital micromirror design in a single light path system, the presentinvention may also employ other types of light modulators and light pathdesigns. For example, fiber-optic cables 72 may be arranged for amultiple light path design to transmit light to three primary colordedicated LCD optical modulators, or to three primary color dedicatedDMD optical modulators. In the case of an LCD optical modulation device,selective transmission of light comprises selective passage of lightthrough a liquid crystal medium on a pixel by pixel basis.

In addition, although base 12 of FIG. 1 has been primarily describedwith respect to components dedicated to projection functionality, it isunderstood that base 12 may be inclusive in a larger system, or comprisecomponents not directed solely to display device 10 output. For example,base 12 may be part of a computer housing that includes components forprojection functionality and components for computer functionality in acomputer system, such as a desktop computer. Computer functionalitycomponents may include a processor, a hard drive, one more interface andcontrol boards, a disk or floppy drive, etc. In this case, housing 20 isconsiderably larger to accommodate the combined functionality andcomponents. In addition, some components may be shared, such as a powersupply and fans used for movement of air within the housing.

FIG. 4A illustrates a cutaway front view of a positional interface 200,taken through a vertical midplane of a bendable corrugated tubing 202and showing select internal components of display device 10 tofacilitate discussion, in accordance with one embodiment of the presentinvention.

Positional interface 200 allows a user to deflect bendable tubing 202and position projection chamber 14 when a threshold force or greater isapplied to the tubing. Interface 200 also maintains a constant positionbetween projection chamber 14 and base 12 when the threshold force isnot applied. The threshold force may be applied either directly totubing 202 or indirectly to tubing 202, e.g., via manipulation ofprojection chamber 14 relative to base 12. In one embodiment, thethreshold force is greater than a maximum force transmitted ontobendable tubing 202 by the weight of projection chamber 14 for anyposition of the projection chamber. This allows positional interface 200to hold a desired position of projection chamber 14 during usage withoutmovement of the projected image. In addition, the threshold force may beincreased by a buffer factor to achieve robust support of projectionchamber 14, or to achieve a desired compliance and resistance for userinteraction.

Mechanical design and assembly of positional interface 16 establishesthe threshold force. Bendable corrugated tubing 202 is strong enough tohold a position for projection chamber 14, while compliant enough for auser to bend tubing 202 to achieve a desired position and orientationfor projection chamber 14. Bendable tubing 202 is hollow on its insideand includes an inner channel 206. Corrugated aluminum shielding orarmor used in the protection of electrical wiring and available from avariety of vendors is well suited for use as bendable corrugated tubing202. The dimensions of tubing 202 depend on the tubing material andconstruction. In one embodiment, bendable tubing is made of a metal suchas aluminum and has an outer diameter between about 0.25 inches andabout 0.75 inches. An outer diameter of 0.5 inches is suitable fordisplay device 10 of FIG. 1.

A lower end 202 a of bendable tubing 202 couples to a top surface 22 aof base 12. Specifically, lower end 202 a of bendable tubing 202 iscoupled to base 12 proximate a center of mass 23 for base 12. An upperend 202 b of tubing 202 couples to receiving interface 29 of projectionchamber 14. Similarly, upper end 202 b of bendable tubing 202 couples toprojection chamber 14 proximate to a center of mass 25 for projectionchamber 14. As described above with respect to FIG. 1, coupling bendabletubing 202 to the center of mass for both projection chamber 14 and base12 minimizes moments produced by positioning of projection chamber 14away from the center mass of base 12. Coupling between two objects asdescribed herein is meant in its broadest sense and may comprise, forexample, joining, permanent or semi-permanent attachment, mechanicallinkage between the two objects, fastening together using a screw orsimilar fastening instruments, connection via a coupler such as amoveable joint or hinge, and coupling through intermediary components.In one embodiment, ends 202 a and 202 b detachably screw into housing 20of base 12 and receiving interface 29 of projection chamber 14,respectively.

In another embodiment, positional interface 200 includes an intermediaryattachment collar 204 disposed at either end of tubing 202. Collar 204is a rigid structure that facilitates permanent attachment betweenbendable tubing 202 and base 12 (or projection chamber 14), and alsoincreases structural support for longer tubing 202. Collar 204 maycomprise a suitably rigid material or metal such as a rigid plastic oraluminum. In the case where both tubing 202 and collar 204 are made ofaluminum, tubing 202 inserts within an inner diameter of collar 204 andis fixed therein by stamping collar 204 on opposite sides. For rigidplastic composition, tubing 202 may be glued to collar 204. Screwingthreads may also be used for attachment between bendable tubing 202 andbase 12 (or projection chamber 14). Bottom or top collar 204 may extenda percentage of the length of tubing 202 to increase strength and heightfor positional interface 200. For example, bottom collar 204 may extendfrom about 10 percent to about 60 percent of the height of tubing 202and collar 204 combined.

A plastic sleeve 212 is disposed circumferentially outside bendabletubing 202 along the entire length of tubing 202. Plastic sleeve 212 isused for aesthetic purposes and matches the color for housing 32 ofprojection chamber 14 and housing 20 of base 12. In another embodiment,plastic sleeve 212 is not used and bendable tubing 202 is matched incolor to housing 32 and housing 20.

Channel 206 extends inside of tubing 202 from lower end 202 a to upperend 202 b. Channel 206 is suitably sized to receive fiber-optic cable208, electrical connectors 209, and air duct 210. Fiber optic cable 208passes through channel 206 and has a first end 208 a in base 12 and asecond end 208 b in projection chamber 14. Electrical connectors 209provide electrical and digital communication between components withinprojection chamber 14 and components within base 12, such as digitalcommunication between optical modulation device 102 and controlcircuitry 76. Air duct 210 also passes through channel 206 and has afirst end 210 a in base 12 and a second end 210 b in projection chamber14. In one embodiment, fiber-optic cable 208, electrical connectors 209,and air duct 210 are designed and arranged with enough slack to allowmovement of projection chamber 14 without placing potentially harmfultensions on cable 208, connectors 209, and duct 210 for any position ofprojection chamber 14. A plastic or rubber sleeve 214 is disposed on theinside ends of channel 206 and prevents fiber-optic cable 208,electrical connectors 209, and air duct 210 from impingement on pointedcorners at either end channel 206.

As shown in FIG. 4A, a top end of air duct 223 is expanded to a thinrectangular profile that increases of the top inlet area of air duct 210and matches the width of optical modulation device 102. In operation,fans 62 within base 12 create a negative pressure at the bottom end 210a that draws air in through the top end 210 b and rectangular profile223 according to its increased inlet area, which spans the width ofoptical modulation device 102. With vents 118 disposed in housing 32 onthe top side of optical modulation device 102, this creates a coolingair flow across the entire surface of device 102. During non-usage whendisplay device 10 is upright, vents 118 also allow hot air in thevicinity of optical modulation device 102 to rise and escape fromprojection chamber 14, thereby providing passive cooling of opticalmodulation device 102 during non-usage.

In one embodiment, bendable tubing 202 is relatively long and allowsprojection chamber 14 to be pointed down onto a surface 220 that base 12rests upon, such as a table. This allows display device 10 to be used inenvironments such as libraries and coffee shops where a user has tablespace but not wall space. A tubing 202 length between about 1 inch andabout 24 inches is suitable for many applications. In a surface usageembodiment, bendable tubing 202 has a length between about 6 inches andabout 24 inches. In another specific embodiment, bendable tubing 202 hasa length between about 2 inches and about six inches.

FIG. 6A illustrates a cutaway side view of a positional interface 200,taken through a vertical midplane of a bendable tubing 202 and showingselect internal components of display device 10 to facilitatediscussion, in accordance with another embodiment of the presentinvention. FIG. 6B illustrates a top view of display device 10 andpositional interface 200 with projection chamber 14 in a collapsedposition. FIG. 6C illustrates a front view of base 12 with bendabletubing 202 removed to show the portions of base 12 for receiving tubing202.

Positional interface 200 allows a user to position projection chamber 14relative to base 12 and comprises bendable tubing 202. Referring to FIG.6A, a lower end 202 a of tubing 202 couples to base 12 while an upperend 202 b of tubing 202 couples to receiving interface 29 of projectionchamber 14. Bendable tubing 202 allows a user to position projectionchamber 14 relative to base 12 when a threshold force or greater isapplied to the tubing, and is similar to that described above withrespect to FIG. 4A.

The position of projection chamber 14 shown in FIG. 6A is suitable foruse when projecting video output. It is understood that a user may bendand twist bendable tubing 202 to change the direction of projected videooutput from projection timber 14 relative to base 12, thereby relocatingthe projected video output. For example, the user may twist bendabletubing to change the direction of video output from the front 12 b ofbase 12 to the side 12 c of base 12, or vice versa.

FIG. 6B illustrates display device 10 and positional interface 200 in acollapsed position. The collapsed position is suitable for use whenprojecting video output and suitable when video output is not projected.When projecting video output in the collapsed position, display device10 somewhat resembles the flat profile of a traditional cinder blockprojector design—but allows simple positioning of projection chamber 14and corresponding projected output by bending or twisting bendabletubing 202. When not projecting video output in the collapsed position,display device 10 provides a flat profile that is suitable fortransport, storage, or placement into a protective carrying apparatus.

To facilitate the collapsed position shown in FIG. 6B, base 12 includesa recessed channel 219. Recessed channel 219 at least partially receivesbendable tubing 202 and interface 29 of projection chamber 14 such thatthe profile or height of display device 10 is lower when projectionchamber 14 and tubing 202 are in the collapsed position. The lowerprofile simplifies display device 10 storage and transport. In oneembodiment, channel 219 includes a height 221 (FIG. 6A) that fullyreceives tubing 202. In addition, channel 219 includes an expansiveopening 219 a at the front end 12 b of base 12 that receives interface29 of projection chamber 14. The expansive opening 219 a is dimensionedto accommodate the shape of interface 29, thereby providing a lowerprofile the collapsed position shown in FIG. 6B.

Display device 10 may also include a clamp or receiving collar 227 thatreceives bendable tubing 202 when in the collapsed position. The collarmay comprise two semi-compliant plastic clips dimensioned and arrangedto receive and press around tubing 202 when inserted therein, andthereby provide a holding force for tubing 202 when in the collapsedposition that maintains the collapsed position, e.g., during transport.

As shown in FIGS. 6A and 6B, bendable tubing 202 couples to base 12towards an aft end 12 a of base 12. Location of channel 219 at one endof base 12 permits channel 219 to span a large portion of the length 231(FIG. 6B) for base 12 and receive the entire length of tubing 202 andprojection chamber 14 in the collapsed position, thereby decreasing thelength of display device 10 in the collapsed position, which is usefulduring transport and to increase portability of device 10.

In another embodiment, bendable tubing 202 couples to base 12 such thatthe forward and aft ends of projection chamber 14 align with, orcontained within, the side dimensions of base 12. Thus, if tubing 202couples to projection chamber 14 away from a midpoint between theforward and aft ends 14 a and 14 b of projection chamber 14, similaroffset is used in the coupling between tubing 202 and base 12 in widthdirection 233 (FIG. 6B) such that the forward and aft ends 14 a and 14 bof projection chamber 14 align with the sides of base 12. In a specificembodiment, base 12 has a width 233 that is greater than a length ofprojection chamber 14 from forward end 14 a to aft end 14 b. In thiscase, ends of projection chamber 14 are within the dimensions of eachside of base 12 when projection chamber 14 is in the collapsed position.Maintaining a profile on both sides of base 12 without extension ofprojection chamber 14 outside of either side of base 12 simplifiestransport and storage, e.g., in a protective carrying apparatus, ofdisplay device 10 when in the collapsed position and when video outputis not projected.

In one embodiment, projection chamber 14 is substantially cylindricaland base 12 has a height 235 (FIG. 6C) greater than or about equal tothe diameter of projection chamber 14. Again, when in the collapsedposition of FIG. 6B, this dimensioning simplifies transport and storageof display device 10 when video output is not projected.

FIG. 4B illustrates a cutaway front view of display device 10 and apositional interface 250, showing select internal components tofacilitate discussion, in accordance with another embodiment of thepresent invention. Interface 250 comprises a ball 252 and socket 254combination that permits relative rotational movement between projectionchamber 14 and base 12.

Ball 252 includes a ball portion 252 a and a coupling portion 252 b.Coupling portion 252 b is a rigid member fixed to base 12 on one end andto ball 252 a on the other end. Coupling portion 252 b providesclearance for projection chamber 14 so projection chamber 14 does notcollide with base 12. In one embodiment, coupling portion 252 b attachesto housing 20 of base 12 proximate a center of mass 23 for base 12.Socket 254 attaches to projection chamber 14 and couples to housing 32of projection chamber 14 at receiving interface 29. In one embodiment,socket 254 attaches to housing 32 proximate to a center of mass 25 forprojection chamber 14. As described above, coupling ball 252 and socket254 to the center of mass for both projection chamber 14 and base 12minimizes any moments produced by positioning of projection chamber 14.While the embodiment in FIG. 4B illustrates coupling of ball 252 to base12 and coupling of socket 254 to projection chamber 14, it is understoodthat the two may be switched and ball 252 coupled to projection chamber14 while socket 254 is coupled to base 12.

Ball 252 cooperates with socket 254 to allow projection chamber 14 to bemoved relative to base 12 and allow projection chamber 14 to maintain aconstant position relative to base 12 after being moved. Ball 252 andsocket 254 thus provide two rotational degrees of freedom betweenprojection chamber 14 and base 12.

Socket 254 includes an inner receiving surface that matches outersurface dimensions of ball 252. Dimensioning between the two surfaces issuch that ball 252 and socket 254 a) allow rotational movement betweenthe two surfaces and allow a user to position projection chamber 14 whena threshold force or greater is applied to the ball and socket, and b)provide sufficient resistance between the two surfaces to holdprojection chamber 14 at a desired position. Thus, when the thresholdforce is not applied, ball 252 and socket 254 maintain a constantposition between projection chamber 14 and base 12. In operation, a usertypically operates the two-degree of freedom joint by manually movingprojection chamber 14 while holding base 12. Similar to design andconfiguration of tubing 202, the threshold force for ball 252 and socket254 is greater than a maximum force transmitted onto ball 252 and socket254 by the weight of projection chamber 14 for any position of theprojection chamber. This allows positional interface 250 to holdprojection chamber 14 during usage without movement of the projectedimage. In addition, the threshold force may be increased by a bufferfactor to achieve robust support of projection chamber 14 without drift;or to achieve a desired resistance for user interaction.

Ball 252 and socket 254 also comprises an inner channel 256. Channel 256extends inside ball 252 and socket 254 from socket 254, through the topof ball portion 252 a, to the bottom of coupling portion 252 b, and intobase 12. Channel 256 is suitably sized to receive fiber-optic cable 258,electrical connectors 259, and air duct 260. Fiber optic cable 258passes through channel 256 and has a first end 258 a in base 12 and asecond end 258 b in projection chamber 14. Electrical connectors 259pass through channel 256 and provide electrical and digitalcommunication between components within projection chamber 14 andcomponents within base 12. Air duct 260 also passes through channel 256and has a first end 260 a in base 12 and a second end 260 b inprojection chamber 14. In one embodiment, cable 258, connectors 259, andduct 260 are designed and arranged with enough slack to allow movementof projection chamber 14 without placing potentially harmful stresses oncable 208, connectors 209, and duct 210 for any position of projectionchamber 14. A plastic or rubber sleeve 264 is disposed on inside edgesof channel 256 and prevents cable 258, connectors 259, and duct 260 fromimpingement on pointed corners at the lower end channel 206.

Channel 256 opens to a top opening 255 of ball 252. Mechanical limitwalls 267 are attached to socket 254, and extend down from socket 254into top opening 255. The mechanical limits 267 are disposedcylindrically within top opening 255 and cooperate with inner walls ofchannel 256 to set limits for displacement between ball 252 and socket254. In other words, limit walls 267 restrict the range of motion forball 252 and socket 254. A cylindrical opening within mechanical limitwalls 267 is configured large enough to receive fiber-optic cable 258,electrical connectors 259, and air duct 260 without impingement for anyposition of socket 254 relative to ball 252. Mechanical limit walls 267may also be rounded or designed to prevent fiber-optic cable 208,electrical connectors 209, and air duct 210 from impingement on pointedcorners of ball 252 and socket 254.

In one embodiment, socket 254 is disposed as a portion of receivinginterface 29 and housing 32 of projection chamber 14. In this case,coupling of a top end of fiber-optic cable 258 to relay optics occurswithin socket 254/receiving interface 29.

FIGS. 4C, 4D, 4E, and 4F illustrate external front, side, top, and sideviews, respectively, of a display device 10 including a positionalinterface 270 in accordance with another embodiment of the presentinvention. FIG. 4D illustrates display device 10 when arm 272 iselevated, while FIG. 4F illustrates display device 10 when arm 272 islowered. Positional interface 270 allows projection chamber 14 to bemoved relative to base 12 and allows projection chamber 14 to maintain aconstant position relative to base 12 after being moved. Interface 270comprises an arm 272, joint 274, joint 276, and wrist joint 280.

Arm 272 is a substantially rigid member having a first end 272 a and asecond end 272 b. Arm 272 is long enough to provide clearance forprojection chamber 14 above base 12 such that projection chamber 14 mayrotate and re-position without interference from base 12. A moldedplastic or hollow metal is suitable for material use with arm 272. Inone specific embodiment, arm 272, housing 32 of projection chamber 14and housing 20 of base 12 are made from a semi-transparent moldedplastic.

Joint 274 couples the first end 272 a of arm 272 to a side wall 222 ofbase 12 and allows rotation and movement between arm 272 and base 12.More specifically, arrow 271 illustrates the rotation provided by joint274, which allows rotation of arm 272, joint 276 and projection chamber14 about an axis perpendicular to a side of base 12 (FIG. 4D). In oneembodiment, joint 274 comprises an outer cylindrical sleeve 282 thatrotates about an inner cylindrical axle 284. Outer cylindrical sleeve282 and inner cylindrical axle 284 are sized and press fit together inassembly of display device 10 such that inner cylindrical sleeve 282press fits into outer cylindrical axle 284. The press fit anddimensioning of sleeve 282 and axle 284 is such that a user may move arm272 relative to base 12 when a threshold force or greater is applied bythe user to arm 272. In addition, the press fit provides sufficientresistance between the sleeve 282 and axle 284 surfaces to holdprojection chamber 14 at a desired position when the threshold force isnot applied. In one embodiment, the threshold force for sleeve 282 andaxle 284 is greater than a maximum force transmitted onto joint 274 bythe weight of projection chamber 14 for any position of the projectionchamber. This allows positional interface 270 to hold a position ofprojection chamber 14 during usage without movement of the projectedimage.

In another embodiment, joint 274 uses an adjustable screw 284 thatallows a user to change a holding force provided by joint 274 betweenarm 272 and base 12 (FIG. 4D). Turning screw 284 clockwise tightensjoint 274 and increases the holding force on arm 272, while turningscrew 284 counterclockwise loosens joint 274 and decreases the holdingforce. In one embodiment, the holding force provided by screw 284 isproportional to the rotational position of screw 284. In anotherembodiment, screw 284 includes a number of distinct holding states, suchas: a) a first state that provides a holding force that is greater thana maximum force transmitted onto arm 272 by the weight of projectionchamber 14 for any position of projection chamber 14, and b) a secondstate that allows arm 272 to be moved relative to base 12.

Joint 276 couples the second end 272 b of arm 272 to projection chamber14 and allows rotational movement between arm 272 and projection chamber14. More specifically, arrow 277 illustrates the rotation provided byjoint 276, which allows rotation of projection chamber 14 about an axisperpendicular to a side of projection chamber 14 (FIG. 4D). In oneembodiment, joint 276 comprises an outer cylindrical sleeve and innercylindrical axle similar to that described above with respect to joint274. In another embodiment, joint 276 comprises an adjustable screw 286similar to screw 284 described above. With either arrangement, joint 276allows projection chamber 14 to be moved relative to base 12 when athreshold force has been applied to joint 276, and allows projectionchamber 14 to maintain a constant position relative to base 12 when thethreshold force is not applied and after being moved. Although joints274 and 276 are described with respect to two specific arrangements, itis understood that other hinged joints, flexures and angular jointdesigns are known to those skilled in the art and may be used.

In one embodiment, positional interface 270 also includes a wrist joint290 that permits rotation of projection chamber 14 and arm 272 aboutaxis that passes through arm 272. Arrow 273 illustrates the rotationprovided by joint 290, which allows rotation and positioning of joint276 and projection chamber 14 about arm 272 (FIG. 4C). Joint 290comprises an outer screw that allows user to manually tighten joint 290for holding a desired position and loosen joint 290 for acquiring adesired position. As shown, wrist hinge 290 is disposed at the secondend 272 b of arm 272. Joint 290 may also be placed elsewhere along arm272, such as the midpoint of arm 272 or first end 272 a.

Although positional interface 270 is illustrated with three joints 274,276 and 290, two joints are also possible. For example, joint 290 may beomitted from the design, leaving joints 274 and 276 as the twooperational joints to move and position projection chamber 14. Inanother dual joint positional interface 270 embodiment, positionalinterface 270 is disposed on a top wall or surface of base 12 and joint274 is not used, while joint 290 is disposed at the top wall or surface.This creates a two joint system where joint 290 permits rotation of arm272 relative to the base 12 about a vertical axis perpendicular to thetop surface, and joint 276 permits rotation of projection chamber 14relative to arm 274 about an axis perpendicular to arm 272. This designis suitable for use with a computer system where a computer tower orsimilar structure acts as base 12. The computer system comprisescomputer system components within base 12; and positional interface 270is then arranged on an upper portion of the computer tower.

Mechanical stops may be implemented for one or more joints of positionalinterface 270 to limit range of motion for each joint. As shown in FIG.4D, joint 274 includes a 135 degree range of motion 291 defined bymechanical stops included within joint 274. At one end of range ofmotion 291, arm 272 is parallel to a bottom surface of base 12 (FIG.4E). At the other end of range of motion 291, arm 272 allows positioningof projection chamber above base 12. In one embodiment, joint 276includes a 180 degree range of motion 293, as shown in FIG. 4D. Thefirst 135 degrees allow protection chamber 14 to travel from upwardpointing angle 293 a to an angle 293 b that is parallel to arm 272.Before projection chamber 14 and joint 276 are rotated to angle 293 b,wrist joint 290 may be used to rotate joint 276 and projector 14 suchthat projection chamber 14 is on an opposite side of arm 272 than base12. This allows display device 10 to be collapsed to a flat profile asshown in FIG. 4E, e.g., for travel. In this position, display device 10may be used on a flat surface as would a conventional cinder blockprojector. Since projection chamber 14 is upside-down in FIG. 4Erelative to its orientation in FIG. 4C, software included with displaydevice 10 may allow a user to vertically flip an output image fromprojection chamber 14. The remaining 45 degrees of joint 276 allowprotection chamber 14 to be rotated upwards when used in the positionshown in FIG. 4E, as shown in FIG. 4F.

Cumulatively, the three joint positional interface 270 thus cooperate toprovide a) a first position for projection chamber 14 that is above base12 when base 12 rests on a flat surface, and b) a second position forprojection chamber 14 that is beside base 12 when the base rests on theflat surface. To prevent tipping for the embodiment shown in FIGS. 4Eand 4F, display device 10 may be designed, and internal componentswithin base 12 arranged, such that the center of mass 295 display device10 is within a stability space provided by high friction pads 18included in the bottom of base 12.

Similar to the design shown in FIGS. 4A and 4B, positional interface 270comprises an air duct 296, electrical connectors 297 and fiber opticcable 298 that pass from base 12, through joint 274, through arm 272,through joint 276, and into projection chamber 14. In one embodiment,slack is given to duct 296, connectors 297 and cable 298 to permit themotion between projection chamber 14 and base 12. In another embodiment,duct 296 and connectors 297 are spiraled similar to a telephone wireused between a headset and base to permit the motion between projectionchamber 14 and base 12.

FIG. 5A illustrates a process flow 300 for projecting video output froma display device in accordance with one embodiment of the invention.Video output from a display device described herein comprises lightmodulated according to video data included in a video signal. Forexample, the video output may include a single image repeatedlydisplayed at the projector refresh rate over time, or for motion picturevideo output, a continuous sequence of images individually modulated bythe optical modulation device.

Process flow 300 begins by projecting video output towards a firstlocation (304). Typically, this occurs in response to receiving userinput for a desired projection lens direction (302), e.g., the usermanipulates the display device and points a projection lens included inthe display device in a first direction directed at the first location.One option for pointing a projection lens according to projector designsprovided above includes positioning projection chamber 14 while the userholds base 12. Alternately, a user may position the projection chamber14 and point projection lens 37 without holding base 12 if there issufficient resistance between base 12 and an object that supports base12.

Referring back to FIGS. 1, 2A, and 2B for a brief description ofprojection according to display device 10, light generated by lightsource 64 is collected by fiber-optic interface 70 for transmissionalong fiber-optic cables 72 from base 12 to projection chamber 14. Inone embodiment, light generation may include light produced by a lamp 91that is reflected by a reflecting mirror 93 into an incident surface ofa rod shaped optical integrator 95 (FIG. 2B). The incident light is thenreflected a plurality of times in the rod shape optical integrator 95such that light is about uniform across the flux area before output fromthe optical integrator 95 to one or more condensing lenses andsubsequent transmission into fiber-optic interface 70. In anotherembodiment, light generation includes light produced by one or morediode lasers whose output is fed into fiber-optic interface 70. Anoutput fiber-optic interface 104 and lenses 106 and 108 convert lighttransmitted by fiber-optic cable 72 to a size suitable for transmissiononto optical modulation device 102 via reflection within prism 110.

Light propagating through prism component 110 a reflects off a surface110 d at interface 110 c by total internal reflection and forms areflected pre-modulated beam directed towards optical modulation device102. The reflected pre-modulated beam travels through prism component110 a to reach optical modulation device 102. Each mirror in opticalmodulation device 102 reflects light in its ‘on’ state back into prismcomponent 110 a and through interface 110 c without internal reflectionsuch that the light propagates into prism component 110 b and out anexit face 110 e of prism 110. Light output through exit face 110 e ischaracterized by output optical path 31, which propagates through one ormore projection lenses 112 that manipulate image light for enlargeddisplay onto a screen or suitable receiving surface.

An optical path output from the projection lens, such as path 31described above for display device 10, relates the location of aprojected video output to the current projection lens direction andprojection chamber position. Although typically not visible to a user,the optical path characterizes a principal direction of light outputfrom the projection lens. The present invention allows a user to changethe location of light output on a receiving surface, such as a wall, fora projector by pointing the projection lens in one or more desireddirections. For example, a user may point a projection lens and locate aprojected image onto a wall between various obstacles on the wall bymanipulating the position of the projection chamber.

At some subsequent time, process flow 300 continues by receiving userinput for a second projection lens direction (306) and projecting thevideo output towards a second receiving surface location (308).Typically, this occurs in response to a user manually pointing aprojection lens included in the display device in a second directiondirected at the second location, e.g., to avoid a new obstacle in theprojection path, or to use a new receiving surface to facilitate viewingby new people. In one embodiment, re-pointing of a projection lens andlocation of projected video output occurs without a user changingpositioning between an object that supports the display device and aportion of the display device that includes the light source thatgenerates light. For display device 10, base 12 includes the lightsource and is not moved between re-positioning of the projected videooutput. A spring-based clip attachment may be secured to base 12 (asdescribed above with respect to FIG. 1) and clipped to a vertical wallsuch as that associated with a cubicle or bookshelf. In this case, theprojection lens may be pointed and re-pointed without changingpositioning between the base and the object that supports the base,namely, the vertical wall. In another embodiment, a base including thelight source rests on a table surface, shelf, one or more books, oranother flat surface or object. Again, the projection lens may bepointed and re-pointed without changing positioning between the baserelative to the surface that the base rests upon.

Cumulatively, the ability to rest base 12 on a flat surface and/or clipbase 12 onto non-horizontal objects allows display device 10 to be usedin a variety of positions and angles not traditionally associated withprojector usage. In environments where no flat surfaces are available,positional interface 200 of FIG. 4A allows a user to bend tubing 202 andorient projection chamber 14 and projection lens 37 to provide ahorizontal image—regardless of the geometry between the object thatsupports base 12 and a horizontal image. For example, when base 12 isclipped sideways onto a vertical wall, tubing 202 may be bent 90 degreesto re-orient projection chamber 14 vertically and allow its projectedvideo output for regular horizontal viewing.

In one embodiment, the first direction and the second direction differby an angle of at least 30 degrees, such as that allowed by any thedevice designs described above. The angular difference may be in alateral direction, a vertical direction, or some combination thereof.For user changes in projection lens direction that alter the laterallocation of the projected image, process flow 300 may also comprisehorizontal keystone correcting the projected image. This typicallyoccurs in response to user input via a keystone correction tool includedwith the projector, or implemented in software on a computer system thatoutputs video data to the projector. Similarly, process flow 300 mayalso comprise vertical keystone correcting the projected image aftervertical image location and direction changes of the projection lensrelative to the base. In another embodiment, the first direction and thesecond direction differ by an angle of at least 60 degrees, aspotentially allowed by one of the positional interfaces described above.Positional interface 200 of FIG. 4A may also permit the first directionand the second direction to differ by at least 90 degrees—verticallyand/or laterally. Positional interface 270 is shown with a 180 degreechange orientation between FIG. 4C and FIG. 4F, for example.

Directional changes such as this are particularly useful to allow imagelocations on different receiving surfaces for the same position of theportion of the display device that includes the light source. Displaydevice 10, for example, permits projection of video output on orthogonalwalls without moving base 12.

FIG. 5B illustrates a process flow 320 for projecting video output froma display device in accordance with another embodiment of the invention.The display device used in process flow 320 permits pointing of aprojection lens onto a surface that the display device rests upon. Forthe display device of FIG. 4A for example, positional interface 200 thatis long enough relative to a minimum throw distance for the projectionlens system such that a user may point the projection lens towards asurface that the display device rests upon, thereby casting an image onthe surface. In one embodiment, the positional interface 200 is longerthan the minimum throw distance. As described above, the corrugatedtubing 202 may have a length between about 12 inches and about 24inches. In this case, the projection lenses in display device 10 aredesigned to have a minimum throw distance from about 12 inches to about18 inches, or less, for example.

Process flow 320 begins by providing a display device, such as one ofthose described above, and base included with the display device forresting on a surface that supports the display device (322). The surfacemay be that included on a table, counter, floor, etc. This allowsprocess flow 320 to occur in environments where wall space is notreadily available. In addition, the surface need not be horizontal. Forexample, the display device may be clipped onto a wall and project animage onto the same wall that supports the device.

Light is then generated within the display device using a light source(324). One or more images are then formed by selectively transmittinglight generated by the light source according to video data included ina video signal provided to an optical modulation device included in thedisplay device. Light generation (324) and image formation (326)suitable for process flow 320 is described above in process flow 300.

In response to a user pointing a projection lens included with thedisplay device towards the surface that supports the display device, thevideo output is projected onto the surface (328). Typically, the imageis projected onto a different portion of the same surface that theprojector rests upon, such as a portion forward from the display devicewhen it rests on a table surface. In one embodiment, the display deviceis designed for short range use and includes a projection lens systemthat aggressively enlarges the image as distance from the projectionlens increases and as the image is projects from the display device.Process flow 320 may also comprise vertical keystone correcting theprojected image in response to user input via a keystone correction toolincluded with the projector.

In one aspect, the present invention divides projection display devicesinto multiple chambers. As described herein, a chamber refers to acompartmented space dedicated to one or more functions of display devicedesign. Display device 10 of FIG. 1 includes two main chambers: a lightsource chamber 65 within base 12 for generating and manipulating lightfor transmission to an optical modulation device; and projection chamber14 for a) housing and servicing an optical modulation device thatselectively transmits light according to image data and b) housing aprojection lens system that outputs a projected image. Display device 10also separates the two chambers with a degree of freedom provided bypositional interface 16.

Multiple chamber configurations of the present invention separate aprojector into multiple compartments and may improve projector designand performance. For example, the multiple chamber design of displaydevice 10 facilitates heat control. Typically, a light source and powersupply contribute the largest share of heat production for a projector.Meanwhile, the optical modulation device requires the strictest heatregulation requirements. The present invention places a light source andpower supply into a chamber separate from a chamber that contains a heatsensitive optical modulation device. In other words, the multiplechamber design advantageously keeps heat sensitive components away fromthe heat generating components, thereby easing temperature control ofthe heat sensitive components. The multiple compartment design alsofacilitates control of heat conduction through a projector. Morespecifically, heat conduction may be limited and channeled by designbetween multiple compartments to specific paths, e.g., throughpositional interface 16 for heat generated in housing 20 of base 12 thattravels by conduction to housing 32 (and components therein) ofprojection chamber 14. Heat conduction is then more readily controlleddue to the limited and known paths of heat conduction. For example, oneor more rubber seals that reduce heat conduction may be placed at thecoupling between positional interface 16 and housing 20 of base 12 orbetween positional interface 16 and housing 29 of projection chamber 20.

In addition, conventional rectangular static housing projector designsoften conform in size to maximum dimensions of large hardware used tocreate and manage the light. For example, cinder block projector designsare often regulated in a length or width by dimensions of the projectionlens system and regulated in height by a lamp. This often createsconsiderable unused space within the rectangular projector, whichincreases size and encumbrance—and decreases portability—of theprojector. The present invention however enables designers to customizechamber packaging according to component dimensions in each chamber,thereby conforming packaging to components within a chamber andminimizing unused space. This, for example, may allow projection chamber14 to maintain a substantially cylindrical profile that matches theprojection lens system; and may allow base 12 to occupy a smallerfootprint than traditionally allowed by the output projection lenssystem.

Display device 10 may employ design alternatives that reduce deviceweight. In one embodiment, display device 10 is less than five pounds.As mentioned above, walls of housing 32 and housing 20 may comprise alightweight and stiff molded plastic or aluminum that reduces overallweight of display device 10. In addition, embodiments including diodelasers for generating light reduce the weight of display device 10relative to designs that employ a white light lamp and their associatedlight manipulation components, such as a color wheel, relay optics,color wheel motor, etc. In another embodiment, display device 10 is lessthan 2.5 pounds.

With respect to usage, the present invention may receive video data froma range of systems and devices. In addition to personal computers suchas desktop computers and laptop computers, a variety of other computersystems and digital devices may output video data to a display device ofthe present invention. Handheld computers, portable digital assistantsand portable digital devices such as cellular telephones areincreasingly integrating computer-related and video functionality,including the ability to access the resources of an external networksuch as the Internet and the ability to output video data to an externaldisplay device. Other portable digital devices such as portable videogames, portable digital video recorders and digital cameras may alsoprovide video output to display device described herein. One currenttrend is hybrid entertainment devices that integrate the functionalityof computer systems, stereos, and televisions. In addition, set-topboxes associated with cable television services are becoming much moresophisticated user interfaces as interactive services become availableto cable customers. Any of these devices may employ and benefit fromvideo output using a display device as claimed herein. The scope ofdigital computer systems is expanding hurriedly and creating manysystems and devices that may employ the present invention. A merging oftelevision, video, and computer functions into a single device also addsvalue to the present invention since the sensitivity to image qualityand size is high in applications such as motion picture viewing. Videogame consoles that use large display devices may also benefit from thepresent invention. Moreover, those skilled in the art will appreciatethat the invention may be practiced with other computer systemconfigurations, multiprocessor systems, microprocessor-based orprogrammable consumer electronics, minicomputers, mainframe computers,and the like.

To further increase display device 10 endurance on a finite batterypower supply, a computer operating with display device 10 may employ oneor software power schemes that minimize power consumption by the displaydevice. A power scheme is a predefined collection of power options.Common power schemes for a graphics based user interface include a‘plugged in’ scheme and a ‘battery use’ scheme. Power schemes allow auser to tailor and apply customized settings, or use a pre-existingpower scheme as a starting point for a customized power scheme. A powerscheme control provided by the graphics-based user interface allows auser to customize display device response for different power states ofthe computer, operation states for the computer system, and differentdisplay devices. Some exemplary power states include plugged in andbattery use. One software technique employs a more aggressiveconservation power scheme when the display device operates on batterypower and is not in use. Exemplary operation states include laptop useand PDA use. Exemplary graphics components include those that outputvideo information for a word processing program, an Internet Browserinterface, a graphics control, a music player program, and a video game.Display device 10 is well-suited for display of motion pictures andstill photographs onto screens. In addition, display device 10 is alsouseful for conducting sales demonstrations, playing video games, generalcomputer usage, business meetings, and classroom instruction, forexample.

Portable display devices of the present invention may provide projectedimages having an image size ranging from inches to many feet, asdetermined by a user and environment. Image size for a projectortypically depends on mechanical factors such as the distance from theprojector to the receiving surface and a splay angle for the projectionlens. Since many conventional projectors and projectors of the presentinvention may offer image sizes with diagonal spans up to 30 feet, it iscommon for light output by a projector to encounter physicalobstacles—either along a projection path between the projection lens andreceiving surface, at the receiving surface, or both. Obstacles at thereceiving surface often force a user to move a conventional cinder blockprojector closer to the wall to reduce image size. Any obstacles alongthe one-dimensional light path between the projector and receivingsurface also conventionally forced a user to move the cinder blockprojector. In general, cinder block designs only offer one-dimensionaloutput for a video image along an optical output path, which is fixedrelative to the projector's base. When the projector is large and bulky,or needs to rest on a large flat surface such as a table, moving theprojector may not always be simple or feasible. In a room or applicationwhere numerous receiving surfaces are present, but locations to rest aprojector are limited, the one-dimensional link often limits imageplacement and compromises usage.

The present invention, however, enables a user to flexibly locate aprojected image in many positions relative to a single position of thedisplay device. Thus, positioning between a projected image and aprojector may vary three-dimensionally according to two dimensions ofimage placement offered by display devices described above, and a thirddimension based on distance between the projector and receiving surface.This enables a user to avoid obstacles between a projector and areceiving surface, and to maximize image size based on specificconditions. For example, a user may tailor projector output used in aliving room or office to navigate projection path obstacles such asplants, bookshelves, etc., that normally would obstruct the projectionpath and limit where the projector is placed, where the receiving imageis cast, and limit image size.

The present invention also enables new uses for projectors. Cubicles andother portable office environments offer limited space, and often only asingle suitable receiving surface. These confined environments alsooffer limited landing locations to rest a large footprint cinder blockprojector. Conventional cinder block projectors are currently not usedin these environments due to the limited receiving surface space and thelarge number of obstacles that would be encountered between thereceiving surface and the cinder block projector in its select fewpermissible landing locations. The present invention however enables aworker within confined spaces to a) locate the display device in manymore locations due to its smaller footprint, b) readily clip the displaydevice onto vertical walls with a clip attachment as described abovewith respect to FIG. 1, and c) point a projection lens flexibly fromalmost any angle in the cubicle to a single or desired receiving surfacelocation. Flexibly usage such as this also extends to other environmentssuch as vehicles, small offices, and any other confined spaces thatoffer limited receiving surfaces and difficult sites to locate aprojector.

In one embodiment, positional interface 16 is relatively long and allowsprojection chamber 14 to be pointed down onto a surface that base 12rests upon, such as a table. This allows display device 10 to be used inenvironments such as libraries, office desks and coffee shops where auser has table space but not wall space.

In another embodiment, display device is configured to increase displaydevice endurance when relying on limited battery power reserves. Thedevice may then be configured to reduce power consumption within aprojection type display device using one or more hardware or softwareoptions. In one embodiment, an array of diode lasers or non-lasingdiodes generates light for subsequent optical modulation according toimage data. Compared to conventional halogen and other white lightgenerating lamps, diode lasers offer a light generation option thatconsumes significantly less power for a given image luminance. Secondly,power consumption by fans employed for heat management within thedisplay device is decreased since the diode array generatessignificantly less heat than a lamp. The diode array also outputscolored light, thereby eliminating the need for a color wheel and amotor that rotates the color wheel. This eliminates the power requiredfor the color wheel motor. In addition, this reduces the power requiredfor managing heat produced by the color wheel motor. In anotherembodiment, the display device does not include audio output, whichdecreases size and reduces power consumption for the device.

Although the foregoing invention has been described in some detail forpurposes of clarity of understanding, those skilled in the art willrecognize that various modifications may be made within the scope of theappended claims. For example, although the positional interfacesdescribed herein have coupled to the projection chamber from the bottom,it is understood that a positional interface may couple to theprojection chamber from the rear. In this case, an air duct, electricalconnection and optical cabling may extend through the projection chamberto its respective functional location. The invention is, therefore, notlimited to the specific features and embodiments described herein andclaimed in any of its forms or modifications within the scope of theappended claims.

1. A projection-type display device, comprising: a light source forgenerating light; an optical modulation device configured to selectivelytransmit light generated by the light source according to video dataincluded in a video signal provided to the optical modulation device; aprojection lens system configured to output light, transmitted by theoptical modulation device, along a projection path; at least one batterythat stores electrical energy; and an electrical energy transport systemconfigured to transmit electrical energy from the battery to the lightsource and to transmit electrical energy from the battery to the opticalmodulation device.
 2. The display device of claim 1 wherein the at leastone battery is rechargeable.
 3. The display device of claim 1 furthercomprising an inlet power port adapted to receive a power cord that isconfigured to electrically couple the display device to an AC powersource.
 4. The display device of claim 1 wherein the at least onebattery stores a maximum of 200 watt hours of electrical energy.
 5. Thedisplay device of claim 4 wherein the at least one battery stores amaximum of 100 watt hours of electrical energy.
 6. The display device ofclaim 1 wherein the light source comprises an array of diode lasers. 7.The display device of claim 6 wherein each diode laser in the arrayconsumes less than about 10 watts when generating light.
 8. The displaydevice of claim 1 further comprising a fan that moves cooling airthrough internal portions of the display device and receives electricalenergy from the battery via the electrical energy transport system. 9.The display device of claim 1 wherein the display device weighs lessthan 2.5 pounds.
 10. The display device of claim 1 wherein the displaydevice is configured to consume less than about 50 watt s when producinglight and projecting an image.
 11. A display device, comprising: a basethat includes a) a housing, b) a light source within the housing forgenerating light, and c) at least one battery within the housing thatstores electrical energy; a projection chamber that includes a) aprojection chamber housing, b) an optical modulation device configuredto selectively transmit light generated by the light source according tovideo data included in a video signal provided to the optical modulationdevice, and c) a projection lens system for outputting light,transmitted by the optical modulation device, along a projection path; apositional interface, coupled to the base and coupled to the projectionchamber, that allows the projection chamber to be moved relative to thebase and allows the projection chamber to maintain a constant positionrelative to the base after being moved; and an electrical energytransport system configured to transmit electrical energy from the atleast one battery to the light source and to transmit electrical energyfrom the at least one battery in the base, through the positionalinterface, and to the optical modulation device in the projectionchamber.
 12. The display device of claim 11 wherein the at least onebattery is rechargeable.
 13. The display device of claim 11 furthercomprising an inlet power port adapted to receive a power cord that isconfigured to electrically couple the display device to an AC powersource.
 14. The display device of claim 11 wherein the at least onebattery stores a maximum of 200 watt hours of electrical energy.
 15. Thedisplay device of claim 14 wherein the at least one battery stores amaximum of 100 watt hours of electrical energy.
 16. The display deviceof claim 11 wherein the light source comprises an array of diode lasers.17. The display device of claim 16 wherein each diode laser in the arrayconsumes less than about 10 watts when generating light.
 18. The displaydevice of claim 11 wherein the display device weighs less than 2.5pounds.
 19. The display device of claim 11 further comprising at leastone fiber optic cable having a first end in the base and a second end inthe projection chamber.
 20. The display device of claim 11 wherein thedisplay device is configured to consume less than about 50 watt s whenproducing light and projecting an image.